1. Field of the Invention
The present invention relates to a base component for cosmetics or and topical preparations, more specifically relates to a base component for cosmetics and topical preparations (for example, ointments or the like and also of lesser consistency) consisting of 2,6,10,15,19,23-hexamethyltetracosane.
2. Description of the Prior Art
Most of the conventional base components used for cosmetics or topical preparations are generally compositions obtained from natural products, and these compositions are usually composed of various mixtures. For this reason, when these base components, are incorporated into cosmetics or topical preparations, there are problems of safety from the standpoint of irritation to the human skin, and stability against degradation with the lapse of time cannot be sufficiently assured (short shelflife). Especially, the problem of said stability (that is, the stability to the action of microorganisms, and physical and chemical stabilities) in the base components of the cosmetics or topical preparations is that degradation can result in the cosmetics or topical preparations making it unsafe for use on human skin. The difficulty in finding a solution to this problem of stability is due to the fact that a composition having a constant and uniform quality can not be obtained from natural products.
Heretofore, the conventional cosmetics or topical preparations contain a base component consisting of hydrocarbon oils such as, for example, liquid paraffins, a hydrogenated dipentene polymer obtained from turpentine oil and a hydrogenated squalene obtained from the liver oil of deep-sea sharks. Each of these oils, however, is a mixture of various components and may cause irritation to the human skin and, also, is not sufficiently stable against degradation with time. These are important problems to be solved in cosmetics or topical preparations.
It is known that the hydrogenated squalene is a mixture composed mainly of 2,6,10,15,19,23-hexamethyltetracosane. Although the hydrogenated squalene contains, as impurities, minute amounts of a mixture of partially hydrogenated pristane and squalene, it has heretofore been used in the art as a base component which is a relatively safe with regard to human skin applications. The hydrogenated squalene has a high stability to the action of the microorganisms with time and a high non-irritating property compared with other hydrocarbon oils, both of which properties are important for the base components of the cosmetics or topical preparations. However, since the hydrogenated squalene is obtained from a natural source, minute amounts of the impurities mentioned above are inevitably contained therein and the problems caused by these impurities, that is, physical and chemical changes with time and the resulting reduction of the ability for safe use on human skin, cannot be neglected. Furthermore, since the hydrogenated squalene can be prepared from squalene contained in the liver oil of deep-sea sharks, which is not always readily available, the industrial use of squalene is quantitatively limited.
Due to the above-mentioned circumstances, instead of the hydrogenated squalene, use of hydrogenated products of an isoprene polymer has recently been proposed in several references (for example, Japanese Patent Application Laid-Open No. 48647/73 and German Pat. No. 1117107). However, these products contain a number of isomers, and their qualities are far from satisfactory for the base components of cosmetics and topical preparations. This is due to the fact that a satisfactory technique for the selective polymerization of isoprene, that is, the regulation or control of terminal linkages of isoprene molecules during the course of polymerization, such as head-to-tail linkage or tail-to-tail linkage, has not as yet been established in the art.